diff options
| author | Len Brown <len.brown@intel.com> | 2017-01-13 01:11:18 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-05 14:40:25 +0200 |
| commit | 283994074501393b67590220ec8015f60ee670a8 (patch) | |
| tree | 1b7e8c578c0a585518161f76d018d72dfc5bfc99 /arch/x86/kernel | |
| parent | 6baa8c92dab9a43f0b363f1b7d7bd269d5efcf8d (diff) | |
x86/tsc: Add the Intel Denverton Processor to native_calibrate_tsc()
[ Upstream commit 695085b4bc7603551db0b3da897b8bf9893ca218 ]
The Intel Denverton microserver uses a 25 MHz TSC crystal,
so we can derive its exact [*] TSC frequency
using CPUID and some arithmetic, eg.:
TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000)
[*] 'exact' is only as good as the crystal, which should be +/- 20ppm
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/306899f94804aece6d8fa8b4223ede3b48dbb59c.1484287748.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index eea88fe5d969..6e57edf33d75 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -694,6 +694,7 @@ unsigned long native_calibrate_tsc(void) crystal_khz = 24000; /* 24.0 MHz */ break; case INTEL_FAM6_SKYLAKE_X: + case INTEL_FAM6_ATOM_DENVERTON: crystal_khz = 25000; /* 25.0 MHz */ break; case INTEL_FAM6_ATOM_GOLDMONT: |